In recent years, light-emitting devices, each being a combination of a solid-state light-emitting element that emits laser light and a wavelength converter containing phosphors, have been proposed. Such light-emitting devices include a light-emitting device by which the wavelength or spectrum of emitted light is changed to a desired wavelength as a result of the combination of a solid-state light-emitting element and phosphors in accordance with the application.
The problem, however, is that when phosphors are excited with laser light having high output, temperature quenching in which luminous efficiency decreases with an increase in the temperature of the phosphors is significant, and this decreases the output of the light-emitting device. To address the problem described above, Patent Literature 1 (PTL 1) has proposed a light-emitting device that utilizes a single crystal phosphor causing a small degree of temperature quenching.